In a radio access network of mobile telecommunication networks such as global system for mobile communications, wide-band code division multiple access or long-term evolution, monitoring of the radio environment measurements are of importance in order to ensure good network coverage, service quality and high transmission capacity.
For radio environment monitoring, standard radio measurements that are specified by third generation partnership project can be used. The radio measurements are performed by the user equipments and the base stations. This means that no additional probes or measurement equipments, or drive tests are necessary for the radio measurements.
Network management systems are typically used to schedule and activate the radio environment measurements. The measured data is provided to the network management system or to a performance monitoring (PM) system.
In addition to the radio measurements, the user equipments (UEs) and the base stations also report information that can be used for localization, for example timing information of received radio frames, or directly positioning system coordinates of the UEs.
A number of localization technologies are implemented in network management system in order to determine the position of the UEs within the cell.
The localization information, similarly to radio environment statistics (RES) data from the radio environment measurements, is also collected by the base stations and sent to the network management system or the PM system. The localization information may be sent together with or separated from the RES data.
In the management system the localization information is correlated with radio environment measurements and/or other performance measurement data.
The accuracy of the positioning methods can be in the order of 10-100 m. Therefore, in an advanced network management system detailed information is basically available for UEs of each subscriber, actual and past position, user behaviour, etc.
Some of the performance monitoring data includes identities of the UE or the subscribers and localization data of each UE. This may be a problem since this data is therefore available and can be processed by e.g. radio network optimization engineers, who are not authorized to identify individual subscribers and determine their position. Radio network optimization engineers need to localize only RES data and PM data to improve network performance.
Even if the UE or subscriber data are not included explicitly in the PM data, radio network optimization engineers can query PM information in educated ways, and may learn some facts which do not belong to their duty and which could be used to violate subscriber privacy.
PM analysis often requires historical data. The subscriber behaviour and the subscriber itself, based on the behaviour, can be identified based on historical data. For instance, staying at regular positions or travelling in regular routes, the subscriber and his/her UE can be identified, even if the international mobile subscriber identity (IMSI)/international mobile equipment identity (IMEI) are coded.
There is a potential threat, where a rogue user e.g. a rogue radio network optimization engineers of the network management system could destroy the mobile operator's credibility by extracting and disclosing the subscribers' privacy, while collecting and evaluating radio performance data.
Some security techniques limit the access to performance monitoring data to radio network optimization engineers of the network management system, which make radio optimization more difficult. Other security techniques are limited to providing distinguished access rights to different radio network optimization engineers.